<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8" />
  <meta http-equiv="X-UA-Compatible" content="IE=edge" />
  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
  <title>Document</title>
</head>

<body>
  <p>当天登录的用户的用户名是：<span id="currUser">测试账号</span></p>

  <script>
    document.querySelector('#currUser').innerHTML = JSON.parse(localStorage.getItem('userdata')).account
  </script>
</body>

</html>